Adds option to exclude validators for monitors in configuration.
Validators can be excluded by adding the "validators" property to a monitor and listing the names of the validators to be excluded in an array called "excludes"inside indside of "validators".

Example:

"numenta/experiments": {
    "username": "numenta-ci",
    "password": "CHANGE ME",
    "contributors": "http://numenta.org/resources/contributors.csv",
    "validators": {
        "excludes": [
            "Travis Validator"
        ]
    }
}
Small improvement.
Merge remote-tracking branch 'upstream/master' into ValidationConfig
Bug fix.
Merge remote-tracking branch 'upstream/master' into ValidationConfig
Merge pull request #11 from carlfriess/ValidationConfig

Adds option to exclude validators for monitors in configuration.